planet formation Archives

October 27, 2021October 27, 2021 by Evan Gough

This is How You Get Moons. An Earth-Sized World Just got Pummeled by Something Huge.

An MIT-led team has discovered evidence of a giant impact in the nearby HD 17255 star system, in which an Earth-sized terrestrial planet and a smaller impactor likely collided at least 200,000 years ago, stripping off part of one planet’s atmosphere. Credits:Image: Mark A. Garlick

Titanic collisions are the norm in young solar systems. Earth’s Moon was the result of one of those collisions when the protoplanet Theia collided with Earth some 4.5 billion years ago. The collision, or series of collisions, created a swirling mass of ejecta that eventually coalesced into the Moon. It’s called the Giant Impact Hypothesis.

Astronomers think that collisions of this sort are a common part of planet formation in young solar systems, where things haven’t settled down into predictability. But seeing any of these collisions around other stars has proved difficult.

June 7, 2021June 7, 2021 by Paul M. Sutter

Planets may Start Forming Before the Star is Even Finished

An illustration of a protoplanetary disk. The solar system formed from such a disk. Astronomers suggest this birthplace was protected by a larger filament of molecular gas and dust early in history. Credit: NASA/JPL-Caltech/T. Pyle (SSC)

Planets form from the accumulation of countless grains of dust swirling around young stars. New computer simulations have found that planets begin forming earlier than previously thought, when a planet’s star hasn’t even finished forming yet.

April 10, 2021April 10, 2021 by Brian Koberlein

Primordial Asteroids That Never Suffered Massive Collisions all Seem to be Larger Than 100 km. Why?

2004 EW95, seen in this artist view, may be a primordial asteroid. Credit: M. Kornmesser/European Southern Observatory

Planetary systems form out of the remnant gas and dust of a primordial star. The material collapses into a protoplanetary disk around the young star, and the clumps that form within the disk eventually become planets, asteroids, or other bodies. Although we understand the big picture of planetary formation, we’ve yet to fully understand the details. That’s because the details are complicated.

February 11, 2021February 11, 2021 by Brian Koberlein

It's Starting to Look Like Super-Earths Really are Just Great big Terrestrial Planets

Artists’s impression of the rocky super-Earth HD 85512 b. Credit: ESO/M. Kornmesser

We’ve learned a thing or two about exoplanets in the past several years. One of the more surprising discoveries is that our solar system is rather unusual. The Sun’s worlds are easily divided into small rocky planets and large gas giants. Exoplanets are much more diverse, both in size and composition.

December 1, 2020 by Andy Tomaswick

Spiral-shaped Planetary Disks Should Be More Common. Giant Planets Might Be Disrupting Their Formation

Planetary system formation is a process that involves astounding and complex forces. Humans have only just started trying to understand what goes on in this extraordinarily important phase of the development of new worlds. As such, we are continuing to make new discoveries and come up with better models that better fit the observations that our instruments are able to collect.

The most recent of those improved models was announced by a research team at the University of Warwick. A paper in Astrophysical Journal Letters explores possible reasons for why there is a lack of spiral structures in newly formed protoplanetary discs. Their answer is a simple one: massive planets that form on the outside of the disc might be disrupting the spiral formation.

June 1, 2020June 1, 2020 by Evan Gough

Huge Stars Can Destroy Nearby Planetary Disks

The brilliant tapestry of young stars flaring to life resembles a glittering fireworks display in this Hubble Space Telescope image. The sparkling centerpiece of this fireworks show is a giant cluster of thousands of stars called Westerlund 2. The cluster resides in a raucous stellar breeding ground known as Gum 29, located 20,000 light-years away from Earth in the constellation Carina. Hubble's Wide Field Camera 3 pierced through the dusty veil shrouding the stellar nursery in near-infrared light, giving astronomers a clear view of the nebula and the dense concentration of stars in the central cluster. The cluster measures between six light-years and 13 light-years across. Credits: NASA, ESA, the Hubble Heritage Team (STScI/AURA), A. Nota (ESA/STScI) and the Westerlund 2 Science Team

Westerlund 2 is a star cluster about 20,000 light years away. It’s young—only about one or two million years old—and its core contains some of the brightest and hottest stars we know of. Also some of the most massive ones.

There’s something unusual going on around the massive hot stars at the heart of Westerlund 2. There should be huge, churning clouds of gas and dust around those stars, and their neighbours, in the form of circumstellar disks.

But in Westerlund 2’s case, some of the stars have no disks.

May 25, 2020May 25, 2020 by Evan Gough

This is an Actual Image of a Planet-Forming Disc in a Distant Star System

An image of AB Aurigae from the ESO's VLT and its SPHERE instrument, showing what scientists think is a baby planet forming. Image Credit: ESO/Boccaletti et al.

In 2017, astronomers used ALMA (Atacama Large Millimeter/sub-millimeter Array) to look at the star AB Aurigae. It’s a type of young star called a Herbig Ae star, and it’s less then 10 million years old. At that time, they found a dusty protoplanetary disk there, with tell-tale gaps indicating spiral arms.

Now they’ve taken another look, and found a very young planet forming there.

May 21, 2020May 21, 2020 by Evan Gough

Astronomers Are Sure These Are Two Newborn Planets Orbiting a Distant Star

An artist's illustration of the PDS 70 system, not to scale. The two planets are clearing a gap in the circumstellar disk as they form. As they accrete in-falling material, the heat makes them glow. Image Credit: W. M. Keck Observatory/Adam Makarenko

Planet formation is a notoriously difficult thing to observe. Nascent planets are ensconced inside dusty wombs that resist our best observation efforts. But recently, astronomers have made progress in imaging these planetary newborns.

A new study presents the first-ever direct images of twin baby planets forming around their star.

November 26, 2019November 26, 2019 by Matt Williams

There Could be Planets Orbiting Around Supermassive Black Holes

Artist's impression of planets orbiting a supermassive black hole. Credit: Kagoshima University

Perhaps the greatest discovery to come from the “Golden Age of General Relativity” (ca. 1960 to 1975) was the realization that a supermassive black hole (SMBH) exists at the center of our galaxy. In time, scientists came to realize that similarly massive black holes were responsible for the extreme amounts of energy emanating from the active galactic nuclei (AGNs) of distant quasars.

Given their sheer size, mass, and energetic nature, scientists have known for some time that some pretty awesome things take place beyond the event horizon of an SMBH. But according to a recent study by a team of Japanese researchers, it is possible that SMBHs can actually form a system of planets! In fact, the research team concluded that SMBHs can form planetary systems that would put our Solar System to shame!

October 1, 2019October 1, 2019 by Evan Gough

A Red Dwarf Star Has a Jupiter-Like Planet. So Massive it Shouldn’t Exist, and Yet, There It Is

Artist's illustration of the newfound gas-giant planet GJ 3512b, which circles a red dwarf star. (Image credit: Guillem Anglada-Escude—IEEC/Science-wave, using SpaceEngine.org (CC BY 4.0))

Thanks to the Kepler mission and other efforts to find exoplanets, we’ve learned a lot about the exoplanet population. We know that we’re likely to find super-Earths and Neptune-mass exoplanets orbiting low-mass stars, while larger planets are found around more massive stars. This lines up well with the core accretion theory of planetary formation.

But not all of our observations comply with that theory. The discovery of a Jupiter-like planet orbiting a small red dwarf means our understanding of planetary formation might not be as clear as we thought. A second theory of planetary formation, called the disk instability theory, might explain this surprising discovery.